I would say bad is when we waste money and try to take loans, I have seen many people who have spent their entire salary that month on gambling and later took loans from other people, that too at high interest rates. Of course, I dislike taking loans in such cases.
I don't take loan at all and I am not against those taking it but many people that take loan doesn't calculate how much to be taken in respect with their income. Loan amount is not supposed to be higher or 80-100% up to your income, that amount of loan is dangerous, it destroys yourself and whoever is involved in it. If earning $100 a month, loan amount should be $5 or less.
And many people do not know that loan is addictive, you get used to it little by little until it becomes part of you, so you should be over conscious when taking loan.